Absorption refrigerating system



Dec. 20, 1960 Filed March 15, 1957 K. C. KIRKORIAN ABSORPTION REFRIGERATING SYSTEM 3 Sheets-Sheet 1 INVENTOR Dec. 20, 1960 K. c. KIRKORIAN 2,964,921

ABSORPTION REFRIGERATING SYSTEM Filed March 15, 1957 3 Sheets-Sheet 3 PIC-3.6

INVENTOR. KIRK C. KIRKORIAN ATTORNEYS its rate Kirk C. Kirkorian, South Norwalk, Conn., assignor to Kirk Industries Inc., a corporation of Delaware Filed Mar. 15, 157,Ser. No. 546,407

13 Claims. (Cl. 62-110) This invention relates to an improved method and apparatus adapted to provide a refrigerating system of the type in which a liquid refrigerant is vaporized into a stream of inert gas and then absorbed in a carrier liquid from which it is regenerated as a gas. The refrigerant gas is then condensed and recycled through the system.

In accordance with the present invention, refrigerant gas is regenerated in a generator of novel construction made up of three separate units, a pump, a vapor separating chamber and a boiler. Absorption liquid rich in refrigerant flows into the pump which lifts it into the vapor separating chamber. The liquid then flows down under the influence of gravity from the vapor separating chamber to the boiler from which it returns to the absorption equipment of the system. Hot refrigerant gas that is regenerated in the boiler is fed into the pump where it assists in pumping the rich absorption liquid into the separating chamber and refrigerant gas passes overhead from the vapor separating chamber to the condenser of the system. This construction and flow of material through the generator has proven in practice to be most effective.

One important advantage is that a part of the refrigerant is liberated as a gas from the rich absorption liquid in the vapor separating chamber and this reduces the amount of refrigerant which has to be regenerated in the boiler. Another important advantage is that hot refrigerant gas from the boiler preheats the rich absorption liquid as the liquid enters the pump and the increase in temperature tends to increase the amount of refrigerant gas liberated from the absorption liquid in the vapor separating chamber. At the same time, the hot refrigerant gas is cooled upon contacting the rich absorpnon liquid and as a result the gas passes overhead to the condenser in highly concentrated form. Otherwise a separate liquid analyzer would be required for rectifying hot refrigerant gas coming from the boiler if the system is to operate at a high level of efficiency.

As to refrigeration, refrigeration is provided by vaporizing liquid refrigerant into a stream of inert gas which is done in an evaporator tube which in a household refrigerator is ordinarily associated with the freezing compartment of the refrigerator. It is known that preevaporator coolers which reduce the temperature of liquid refrigerant before it enters the evaporator greatly increase efliciency of refrigeration and although such pre-coolers have been suggested, the apparatus is bulky and difficult to install and the results have not been entirely satisfactory.

The applicant has now devised a very simple and inexpensive form of pre-evaporator cooler which is easy to install and which has been shown in practice to be highly effective. The pre-cooler of applicants invention comprises a single length of pipe which is positioned between the condenser and evaporator of the system and the pre-cooler pipe is preferably separated from the evaporator by means of heat insulation. Liquid refrigerant from the condenser is passed through the precooler pipe on its way to the evaporator and inert gas leaving the evaporator is also passed through the pipe preferably counter-currently to the flow of refrigerant. The inert gas and refrigerant liquid are in actual physical contact, and although the gas which enters the precooler is saturated with refrigerant, at the temperature at which it enters it still has a fairly large capacity for additional refrigerant which readily vaporizes into the gas at the higher temperature which exists in the precooler pipe. Vaporization of small amounts of refrigerant liquid is very effective for reducing temperature of the liquid and since the inert gas entering the pre-cooler is very cold, it also exerts a cooling effect on liquid.

In the preferred form of applicants invention a second pre-cooler of similar construction to the first is employed for precooling inert gas before it enters the evaporator. In this case, excess refrigerant liquid leaving the evaporator flows through the pre-cooler preferably countercurrently to the inert gas. The excess liquid leaving the evaporator contains a small residual amount of refrigerant which vaporizes into the inert gas to produce a cooling effect and physical contact between inert gas and cold spent liquid also increases the cooling effect on the gas.

Another feature of applicants invention involves the construction of heat exchange equipment in which cold inert gas rich in refrigerant flows countercurrently to inert gas poor in refrigerant coming from absorption equipment. The heat exchanger includes an inner pipe and an outer pipe with an annular opening between them and in the exchanger of applicants invention, a plurality of fins have been provided to deflect the flow of gas through the annular opening so that the gas follows a serpentine path as it passes through the exchanger. The deflecting fins also provide a certain amount of turbulence in the flow of gas which prevents streamline flow through the exchanger. As a result of turbulence the heat exchange is highly eflicient and this is reflected throughout the system.

These and other advantages of the improved refrigeration system of applicants invention may be readilyunderstood by reference to the accompanying drawings in which:

Fig. 1 is a schematic view of the rear of a household refrigerator illustrating refrigerating apparatus built in accordance with applicant's invention. In this view part of the refrigerator cabinet has been broken away in order to illustrate the structure of the entire system;

Fig. 2 is a side view of the apparatus of Fig. 1;

Fig. 3 is a detailed cross sectional view of the heat exchanger of the apparatus of Fig. 1;

Fig. 4 is taken on line 44 of Fig. 3;

Fig. 5 is an isometric enlarged view of part of the heat exchanger of Fig. 3; and

Fig. 6 is an enlarged view of the generator and vapor pump units of Fig. 1. Fig. 6 has been enlarged to better illustrate the flow of fluids. The enlarged view is not to scale.

Turning now to the drawings, the drawings illustrate an absorption refrigerating system which may be operated continuously. Of the many known materials which may be employed in such a system, ammonia, hydrogen and water are the three most frequently employed and these materials will therefore be used in describing the present invention. Of course any of the known materials may be used in carrying out the present invention.

Briefly stated, in the continuous absorption refrigerating system shown in the drawings, ammonia gas is fed upwardly from generator unit 10 through an air cooled rectifier 12 into condenser 14 where the gas is condensed to liquid ammonia. Liquid ammonia flows down under the influence of gravity from condenser 14 into evaporator 16 where it vaporizes into a stream of hydrogen gas moving countercurrently through the evaporator. he Y PQ a qr o ause a t ides r gerator and a sh wn i he drawin s e raa at r germ P ss t n a e Wa Q hs f ee in s u a tm m 8 of a hqa s s d e r erant sabinet 9 (F -1 il t gas rich in refrigerant passes out of the top of the evapoata a d han wn t o the nset P pe 2.1 of h exchanger 22 and into a receiver 24. Excess refrigerant liquid from evaporator 16 is fed into the iiow of rich hy ca a n e heat x h er as at 3?- Ri ydro en a item he r c iv r flaws upward y t a s bsb bsr 28 cquutcr urrsn y o a s ream o wa e w in r r n flowing do nw r y thr u h h abs T wa crweak in re ri eran abs rb ammonia from the hydrogen gas and the Water rich in refrigerant flows rom bsorbe to rece er 2.4,- Hvd oge gas st t a r f f ref gera flo upwa ly f om bscr e 28 into evapo a or Where it aga n flow un crcurr n y to liqu d ammo iah wa i i amm n a re r ge ant ows from rec ver 24 throu the shell of a heat exchanger 30 into the generator unit 10 where the ammonia is regenerated as a gas. Water weak in refrigerant flows from the generator through inner pipe 29 of heat exchanger 30 and then through an air cooler section 32 and into absorber 28 as at 34 where the water again absorbs ammonia from rich hydrogen gas. Referring now to the details of the construction of the system, generator 10 is made up of three separate units, a vapor lift pump 36, a vapor separating chamber 38 and a boiler 40. These units stand upright in vertical position in a four-sided open casing 41 positioned at the rear of refrigerator 20 (Fig. 2). The vertical position of the generator is of advantage because horizontal space is limited and the heat from a vertical generator may be channeled upwardly through a relatively small area off to one side away from those units of the system which are air cooled. A particularly effective structure is shown in the drawings where the generator unit '10 is positioned off to one side beyond a vertical line marking the boundary of air cooled units in the system. As best shown in Fig. 1 the vertical side wall on the left hand side of casing 41 comprises a vertical top portion and a vertical bottom portion. The bottom portion is offset from the top portion and positioned out to the left beyond the vertical line of the top portion to provide storage space for the generatorunit of the system outside the vertical line marking the boundary of the air cooled units in the system. The top and bottom portions of'the side wall of the casing are joined by means of a connecting wall which is provided with openings 42 so that heat from generator unit 10 is free to pass through the openings and move upwardly outside the casing.

Water rich in ammonia is gravity fed from the bottom of receiver 24 through pipe 43 into the outer pass of heat exchanger 30 which as shown is coiled around the bottom of generator 10. In passing through heat exchanger 30 the water rich in refrigerant (rich liquor) from receiver 24 is constantly picking up heat from the water (weak liquor) which is being returned from boiler 40 to absorber 28 through pipe 29 which constitutes the inner pass of the exchanger so, that by the time the rich liquor is fed into vapor lift pump 36 by means of pipe 46, its temperature is high enough to liberate some ammonia as a; gas. In order to' prevent ammonia gas'from interfering with'the steady flow of rich liquor a' vent'line 48 is provided which connects the outer pass of heat exchanger 30. with the upper portion of vapor separating chamber 38. Vapor lift pump 36 pumps the rich liquor up through pipe 0 into vapor "separating chamber 38. 'This'is done.

by'me'ans of hot ammonia gas which feeds from the top ofhoiler- 40 through" pipe 52 into "vapor lift pump 36. Vaporlift pump 36 is astandar'd type of pump'and the structural details and'operation of sucha' pump are SQ well known that no useful purpose would be served by describing them herein. m

It will be understood that hot ammonia gas from boiler 40 gives up heat to the rich liquor and as a result some additional amount of ammonia gas is liberated from the liquor in vapor separating chamber 38. As best shown in Fig. l of the drawings the inside diameter of the vapor separating chamber 38 is more than /2 again as large as the inside diameter of any of the conduits used in generator unit 10 so that the chamber provides a reservoir for a pool of rich absorption liquid in which the regenerated gas is analyzed before being released back to the system. The analyzed gas is free to pass off overhead through pipe 54 along with the gas generated in boiler 40. The gas from vent line 48 is also free to flow overhead through pipe 54 and for this purpose it is preferable to position the outlet of vent line 43 above the liquid level in vapor separating chamber 38. Liquid in vapor separating chamber 38, which still contains an appreciable quantity of ammonia, flows under the influence of gravity from the bottom of vapor separating chamber 38 through pipe 56 into boiler ,40.

As shown in Fig. l, boiler 40 comprises a single outer cylindrical chamber-57 which surrounds a pipe 58 having a suitable burner 50 located at the bottom thereof. Burner 60 is preferably a gas burner but if gas is not available any convenient electric, gas, solid, or liquid fuel may be used. Burner 60 is standard equipment for absorption refrigerating systems and the details of its construction will not be described. Pipe 58 transmits the heat of burner at? to the liquid in chamber 57 causing it to liberate hot ammonia gas which as previously described flows downwardly through pipe 52. The hot weak liquor flows under the influence of gravity rout of the bottom of boiler 40 through the inner pipe 22 of heat exchanger 30 into the absorber 28. In passing through pipe 29 on its way to absorber 28 the weak liquor is air cooled and to assist in air cooling the liqui a plurality of air cooling fins 44 are positioned on the pipe as at 32. The liquid levels maintained in generator 10 and receiver 24 are maintained high enough to insure circulation of liquid in the system under the influence of gravity. Details of the exact liquid level as well as the balance of gas pressure in the system which is required to insure the continuous flow of gas and liquid as described herein is well within the knowledge of one possessing ordinary skill in the design and operation of continuous absorption refrigerating systems and no useful purpose would be served by setting forth the details. It is also known that each manufactured unit has its own individual characteristics and each new unit is charged with the proper amount of gas and liquid by a skilled mechanic who balances the amount of materials to insure proper operation before the refrigerator leaves the factory.

Generator 10 has proven to be extremely efficient for regeneration of ammonia gas. One important feature of the generator which materially contributes to its efliciency is the fact that some of the ammonia gas is liberatcd from the rich liquor in vapor separating chamber 38 which relieves the burden on boiler 40 so that the boiler tends to effect a more complete removal of ammonia from the absorption liquid. Another important feature of generator unit 10 is that the temperature of hot ammonia gas from the boiler is reduced by contact with the relatively cool rich liquor, and as a result of such reduction in temperature and physical contact between the gas and rich liquor the refrigerant gas passing overhead from vapor separating chamber 58 is very highly concentrated and there is no need for separate analyzer equipment for rectifying the ammonia gas.

The ammonia gas from vapor separating chamber 38 is air cooled as it flows through pipe 5 4 and the p-ipeis providedwith'a pluralitvof- 'air cooling 'fins'61 positi'oned as at 12 which as'sistin air cooling the gas on its way to condenser 14. Condenser 14 is of ordinary construction and it includes a loop of pipe 62 having the usual air cooling fins 63. As the ammonia gas passes through the condenser its temperature is reduced and under the conditions of pressure maintained in the system the gas soon condenses to liquid ammonia which flows through a connecting pipe 64 into the tube of evaporator 16. The condenser pipe 62, connecting pipe 64 and the tubes of evaporator 16 are slightly inclined downwardly so that liquid ammonia will flow through these units.

Turning now to evaporator 16, the evaporator includes a pre-evaporator cooling tube 66 for the liquid refrigerant and a pre-evaporator cooling tube 68 for hydrogen gas and each of these tubes 66 and 68 are respectively connected to opposite ends of the main evaporator tube 70. As best shown in Figs. 1 and 2 both pre-cooler tubes 66 and 68 are positioned in the heat insulated shell 72 (Fig. 2) of refrigerator box 20 so that the insulation of the box separates these two tubes from main evaporator tube 70. As best shown in Figs. 1 and 2 in order to effect precooling the length of tubes 66 and 68 is at least twice as long as the thickness of the insulated shell 72 of the refrigerator cabinet and in the preferred form of invention shown the length of the precooler tubes 66 and 68 is approximately equal to the length of one of the passes of main evaporator tube 70. The main evaporator tube is positioned on the top, bottom and rear walls of freezing compartment 18 within the interior of the refrigerator box. Liquid ammonia from condenser 14 is fed by means of pipe 64 into one end of pro-evaporator tube 66 and the liquid flows through the pre-cooler tube 66 countercurrently to cold hydrogen gas rich in refrigerant which flows from the main evaporator tube 70 into the second end of the pre-evaporator tube 66. Hydrogen gas entering the pre-evaporator cooler is very cold and under ordinary operating con ditions it has some capacity for additional ammonia vapor and the low temperature of the hydrogen gas and its capacity for a small amount of ammonia vapor make the hydrogen gas extremely eflective in reducing the temperature of the liquid ammonia in the pre-cooler tube 66. As a result the liquid ammonia enters the main evaporator tube 70 at a much lower temperature than it ordinarily would and this increases the cooling efliciency of evaporator 16.

Cooling efficiency of evaporator 16 is also increased by the hydrogen pre-evaporator cooler tube 68. In this case hydrogen gas which flows upwardly through the shell of heat exchanger 22 enters one end of tube 68 and it flows through the tube countercurrently to residual refrigerant liquid which flows from the main evaporator tube 70 into the second end of the hydrogen pre-cooler tube. The residual liquid refrigerant is very cold and it contains some small amount of liquid ammonia which vaporizes into the hydrogen gas. The cooling effect of the cold liquid and the further cooling effect of vaporization of liquid ammonia are highly effective in combination for reducing the temperature of hydrogen gas before it enters main evaporator tube 70. Another feature of the present evaporator is its simple construction which provides a single continuous passageway for the hydrogen and liquid refrigerant which move countercurrently and make a single pass through the evaporator. Another feature of the present evaporator is the loop of tubing 70 positioned on the rear Wall of freezing compartment 18 which eliminates a vertical drop of refrigerant liquid from the top to the bottom of the compartment and this insures a steady even flow of the liquid refrigerant through the evaporator tubing. As is customary in the art'the main evaporator tube 70 is arranged in a serpentine path to pass back and forth over the exterior surface of the freezing compartment 18 and the length of each pass is approximately equal to the 6 distance between opposite side walls of the freezing compartment.

As to hydrogen gas, the hydrogen gas rich in refrigerant flows from evaporator 16 down through the inner pipe 21 of heat exchanger 22 and the residual refrigerant liquid flows out of the hydrogen pre-cooler tube 68 through a pipe 73 which feeds the liquid into the stream of hydrogen gas in pipe 21 as at 26. The hydrogen gas and residual liquid flow down through pipe 21 into receiver 24 and the outlet of pipe 21 is positioned above the level of the rich absorption liquid in the receiver. Heat exchanger 22 is positioned within the insulated shell 72 of the refrigerator (Fig. 2). The hydrogen gas rich in refrigerant flows from the top of receiver 24 through tube 74 of absorber 28 and a plurality of air cooling fins 76 on the tube assist in cooling the hydrogen gas. Weak liquid which enters the absorber tube 34 flows countercurrently to the hydrogen gas into re ceiver 24. As previously described the water absorbs ammonia from the hydrogen gas and the water rich in ammonia passes from the bottom of receiver 24 into generator 10 where ammonia is regenerated as a gas. Hydrogen gas from absorber 28 flows upwardly through the shell of heat exchanger 22 where it is cooled by the cold hydrogen gas moving downwardly into receiver 24. As is known the difference in density of hydrogen gas rich in ammonia and hydrogen gas weak in ammonia causes circulation of the gas in the system.

Turning now to Figs. 3, 4 and 5 of the drawings it will be seen that a plurality of deflecting fins 78 are positioned in the outer annular opening through the shell of heat exchanger 22 and the fins are so arranged that the hydrogen gas is forced to follow a serpentine path up through the shell of the exchanger. These deflecting fins tend to reduce the velocity of the hydrogen gas and at the same time the fins introduce some turbulence and prevent streamlined flow of hydrogen gas through the exchanger. As a result the exchange of heat is materially improved and the temperature of hydrogen gas leaving the exchanger is materially reduced to increase the cooling elfect of the gas in the evaporator.

The deflecting fins in the shell of heat exchanger 22 are provided by means of four generally U shaped channel members 80 each of which are positioned in spaced relationship longitudinally along the length of the exterior of inner pipe 21. Both of the flanges of the U shaped channel members are cut into to provide flaps or deflecting fins 78 which project outwardly from the flanges of the channel members in one direction into the gas passageway formed in each U shaped member and alternate fins 78 project out from the flanges of the channel members in a second direction into the gas passageway between adjacent channel members. The deflecting fins force the hydrogen gas to follow a serpentine path and another advantage of this construction is that the U shaped channel members and fins 78 greatly increase the exterior surface area of inner pipe 21 that is in contact with the hydrogen gas. The channel members and fins also extend the cooling etfect of pipe 21 out away from the surface of the pipe into the body of the stream of gas.

In hot climates or in those cases where the refrigerating system is operating at capacity loads, it may happen that some of the ammonia gas will pass right through condenser 14. In order to take care of this situation applicants provide an expansion chamber 82. One end of the expansion chamber is connected to the outlet of condenser 14 as at 84 by means of pipe 86 and the other end of the expansion chamber is connected by means of a pipe 88 to the stream of rich hydrogen gas flowing downwardly through pipe 21 of heat exchanger 22. Any ammonia gas that is not condensed will flow up into the expansion chamber through pipe 86 and the gas will be condensed to liquid in the expansion chamber which thereafter runs back down pipe 86 into the flow of 7 liquid ammonia leaving condenser 14. The pressure increase caused by the expansion of ammonia gas into chamber 82 is transmitted to the stream of hydrogen gas through pipe 8'8 to maintain the proper pressure balance inthe system.

"It will be understood that it is intended to cover all changes and modifications of the preferred form of invention herein chosen for the purpose -of illustration which do not constitute departures from the spirit and scope of the described invention.

What "I claim is:

1. In a refrigerator structure having an insulated shell and an absorption refrigerating system adapted to operate continuously wherein a refrigerant liquid is vaporized into a stream 'of aninert gas to provide refrigeration, the combination which comprises an evaporator tube positioned in the refrigerating area of the system, said tube having a first and a second end each of which is positioned adjacent the boundary of the refrigerating area, a length of tubing positioned outside said refrigerating area which is at least twice as long as the thickness of the insulated shell and which is separated by heat insulating material from thesaid evaporator tube, said length of tubing being connected to the first end of said evaporator tube, means for feeding astrcam of inert 'gas and liquid refrigerant through said evaporator tube and said length of tubing to bring the inert gas and refrigerant liquid in physical contact with one another for a distance at least twice that of the thickness of the insulated shell of the refrigerator structure whereby one 'of the refrigerating materials may be precooled in the length of tubing before entering the evaporator tube, a second length of tubing connected to the second end of said evaporator tube which second length of tubing is positioned outside said refrigerating area of the system and separated from the said evaporator tube by heat insulating material and which second length of tubing is at least twice as long as the thickness of the insulated shell and means for feeding inert gas and liquid refrigerant through said evaporator tube and said second length of tubing to bring the inert gas and liquid refrigerant into physical contact with each other for a distance at least twice that of the thickness of the insulated shell of the refrigerator structure whereby the inert gas may be precooled in one of said lengths of tubing before it enters the evaporator tube and whereby the liquid refrigerant may be pre-cooled in the second length of tubing before it enters the evaporator tube.

2. A household refrigerator with an insulated shell and a freezing compartment positioned therein, an absorption refrigeration system in which liquid refrigerant is vaporized into a stream of inert gas to provide refrigeration in an evaporator tube, an evaporator tube positioned on the wall of said freezing compartment, a precooler'length of tubing positioned a predetermined distance away from the wall of said freezing compartment which is separated from said evaporator tube by heat insulating material and which length of tubing is at least twice as long as the thickness of the insulated shell of the refrigerator, means for connecting the precooler length of tubing with the evaporator tube and means for feeding inert gas and refrigerant liquid into said precooler tubing to conduct the inert gas and 'refrig'erantliquid in heat exchange relationship for a distance at'least twice that of the thickness of the insulated shell .of the refrigerator whereby one of therefrigerating materials may be precooled before entering the evaporator tube, a second length of precooler tubing positioned a predetermined distance away from the wall of said freezing compartment which pre-cooler tubing is separated from the evaporator tube by heat insulating material the said second length of tubing being at least twice aslong'as the thickness of the insulated shell of the refrigerator, means for connecting the second pre-cooler tube with the said evaporator tube and means for feeding inert"gas'andrefrigerant liquid intosaid second pre-coole'r tubetoconductthe in'ertgas a'ndr'efrig'erant liquidin heat exchange relationship for a distance at least twice that of the thickness of the insulated shell of the refrigerator whereby both of the refrigerating materials may be precooled before entering the main evaporator tube.

3. A structure as specified in claim 2 in which the second length of precooler tubing is positioned in the insulated shell of said refrigerator.

4. In an absorption refrigerating system of the type wherein liquid refrigerant is vaporized into a stream of inert gas in an evaporator protected by an insulated shell to produce a refrigerated area in the system, the method which comprises the steps of bringing liquid refrigerant which is being supplied to the evaporator into physical contact with inert gas in an area removed from the said refrigerated area of the system, conducting said gas and liquid refrigerant in physical contact for a distance at least twice that of the thickness of the insulated shell before said gas and liquid enter the refrigerator area and bringing spent refrigerant into physical contact with inert gas which is being supplied to the evaporator in an area which is removed from the said refrigerated area of the system, conducting said spent refrigerant and inert gas in physical contact for a distance at least twice that of the thickness of the insulated shell before said spent refrigerant and inert gas enter the refrigerator area whereby the liquid refrigerant and inert gas being supplied to the evaporator may be precooled before entering such evaporator.

5. The method specified in claim 4 in which the inert gas and liquid refrigerant are caused to fiow countercurrently to eachother when brought into physical contact.

6. In an absorption refrigerating system adapted to operate continuously the combination which comprises, a heater pipe, a cylindrical boiler for regeneration of refrigeration gas which is coaxially mounted on said heater pipe to surround the same, means of supplying heat to the pipe, a vapor lift pump separated from said boiler, a first conduit connecting the top portion of said boiler with the vapor lift pump for conducting all of the regenerated gas from the boiler into the pump, a heat exchanger coil comprising an inner and an outer pass which surrounds the lower end portion of both the boiler and vapor lift pump, one of said passes being connected to the vapor lift pump to supply rich absorption liquid from the system to the pump, the second pass of said heat exchanger being connected to the boiler to return weak absorption liquid to the system and exchange heat with the rich absorption liquid being supplied to the pump, a vapor separating chamber separated from said boiler and vapor lift pump, a second conduit for conducting rich absorption liquid and regenerated gas from the pump into the top of said separating chamber, the entire length of second conduit being separated from and out of contact with the said heater pipe and boiler, a third conduit connected to the top of said separating chamber for supplying all of the regenerated gas to the system, the inside diameter of said separating chamber being at least /2 again as large as the inside diameter of any of the said conduits so that the separating chamber provides a reservoir for rich absorption liquid in which regenerated gas is analyzed before being released from said liquid to the system.

7. In an absorption refrigerating system adapted to operate continuously the combination which comprises a refrigerator cabinet with a four sided open casing positioned on the exterior of one side wall thereof, one of the side walls of said casing comprising a top vertical portion and a bottom vertical portion which bottom portion is positioned outside the vertical line of the top portion to provide storage space for the generator unit of the system, a connecting wall joining the top and bottom portions of the side wall of the casing, a generator unit in said storage space which is positioned outside the vertical line which marks the boundary of the remainder of the system which is carried in said casing andsaid connecting wall of the casing having openings therein'to 9 allow the heat of the generator to pass through the holes and escape outside the casing.

8. In an absorption refrigerator system of the type wherein a liquid refrigerant is vaporized into an inert gas in an evaporator and is then removed from the gas in absorption equipment, the combination which comprises apparatus for exchanging heat between rich gas being supplied from the evaporator to the absorption equipment and lean gas being supplied from the absorption equipment to the evaporator which apparatus includes an outer casing having an inner pipe therein with smaller outside diameter than the inside diameter of the outer casing to provide an annular opening between said pipe and outer casing, means for supplying rich gas from the evaporator to the inner pipe at one end of the exchanger, and means for supplying lean gas from the absorption equipment to the annular opening in the exchanger at the second end thereof, a plurality of generally U shaped channel members positioned in spaced relationship longitudinally along the length of the exterior surface of said inner pipe with each of the legs of the U shaped channel members projecting out into the annular opening between the outer casing and inner pipe and each of said legs having a plurality of deflecting fins thereon which project into the longitudinal passageway between said legs of the U and a plurality of deflecting fins that project out into the longitudinal passageway between adjacent channel members to deflect the stream of lean gas and cause it to follow a serpentine path through the annular opening between the outer casing and inner pipe.

9. A structure as specified in claim 8 in which the deflecting fins are an integral part of the U shaped channel members which fins are formed by bending a portion of the material of the leg outwardly away from the plane of the body of the leg of said U shaped channel member.

10. In an absorption refrigerating system adapted to operate continuously, the combination which comprises a generator unit that includes a vapor lift pump, a vapor separating chamber and a boiler, said vapor separating chamber being a separate unit positioned in spaced relationship to the boiler, said vapor separating chamber having a first pipe which connects the chamber with the vapor lift pump for feeding rich absorption liquid from the vapor lift pump into the chamber and a second pipe which connects the chamber with the boiler for feeding rich absorption liquid from the chamber into the boiler, said separating chamber having an inside diameter at least one half again as large as the inside diameter of the said first and second pipes so that the chamber provides a reservoir for a pool of rich absorption liquid for analyzing the refrigerated gas liberated from the liquid in such chamber, a third pipe for feeding rich absorption liquid from the absorption system into the vapor lift pump, a fourth pipe for feeding all of the refrigerant gas from the boiler into the vapor lift pump to assist in pumping the rich absorption liquid into the vapor separating chamber, a fifth pipe connected with the vapor separating chamber adapted to carry regenerated refrigerant gas away into the system without again bringing it into physical contact with absorption liquid, means for heating the absorption liquid in the boiler to regenerate refrigerant gas, and a sixth pipe adapted to conduct weak absorption liquid from the boiler back into the absorption system.

11. A structure as specified in claim 10 in which a portion of the sixth pipe has smaller outside diameter than the inside diameter of the third pipe and in which the said portion of the sixth pipe is positioned inside the third pipe to provide an exchange of heat between rich absorption liquid flowing into the vapor lift pump and hot weak absorption liquid flowing away from the boiler of the generator.

12. A structure as specified in claim 10 which includes a vent for refrigerant gas which connects the third pipe with the vapor separating chamber of the generator.

13. A structure as specified in claim 10 in which the boiler of the generator includes a single cylindrical outer chamber for the absorption liquid having a pipe positioned therein which pipe is adapted to transfer heat from the said heating means to the liquid.

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